Endoscopic surgery of a distensible organ, such as a uterus, may be performed with an endoscope that is insertable into the uterus and a resector that passes through the endoscope to cut or otherwise treat tissue in the uterus. During surgery, it often is desirable to distend the uterus with a fluid, such as saline, sorbitol, or glycine, in order provide a visible working space. Fluid can be infused into the uterus and removed from the uterus through the endoscope and/or resector.